Question

Tính nhanh :

A.2004^2-16

B.892^2+892.216+108^2

C.10,2.9,8-9,8.0,2+10,2^2-10,2.0,2

D.36^2+26^2-52.36

E.105^2-25

F.73^2-27^2

Answer 1

\(A=2004^2-16=\left(2004-4\right)\left(2004+4\right)=2000\cdot2008=4016000\)

\(B=892^2+892\cdot216+108^2=892^2+2\cdot892\cdot108+108^2=\left(892+108\right)^2=1000^2=1000000\)

\(C=10,2\cdot9,8-9,8\cdot0,2+10,2^2-10,2\cdot0,2\)

\(=9,8\left(10,2-0,2\right)+10,2\left(10,2-0,2\right)\)

\(=10\cdot\left(9,8+10,2\right)=10\cdot20=200\)

\(D=36^2+26^2-52\cdot36=\left(36-26\right)^2=10^2=100\)

\(E=105^2-25=\left(105-5\right)\left(105+5\right)=100\cdot110=11000\)

\(F=73^2-27^2=\left(73-27\right)\left(73+27\right)=46\cdot100=4600\)

Answer 2

A. 2004²-16=2004²-4²=(2004-4)(2004+4)=2000.2008=2016000
B. 892²+892.216+108²= 892²+2.892.108+108²=(892+108)²=1000²=1000000
C.Khó nhìn quá
D.36²+26²-52.36=36²-2.36.26+26²=(36-16)²=20²=400
E.105²-25=(105-5)(105+5)=100.110=11000
F. 73²-27²=(73-27)(73+27)=46.100=4600